Stereotactic body radiation therapy (SBRT) appears to be an effective treatment for oligometastatic disease in patients with recurrent prostate cancer (PCa), a new study suggests.

Ciro Franzese, MD, of Humanitas Clinical and Research Hospital, Milan-Rozzano, Italy, and colleagues analyzed findings from 64 patients who underwent SBRT for 90 metastases. Fifty patients (78.1%) received SBRT for lymph node metastases, 2 patients (3.1%) were treated simultaneously for lymph node and bone metastases, and 10 (15.7%) were treated for bone metastases only. Two patients received SBRT for lung metastases. Of the 64 patients, 27 were treated with androgen deprivation therapy (ADT) when they underwent SBRT and 37 were not.

The median follow-up was 15.2 months. Rates of local control at 6, 12, and 18 months were 94%, 88%, and 84%, respectively, the investigators reported in Cancer Medicine. Patients with castration-resistant disease had a significant 2-fold increased risk of disease progression than those with castration-sensitive disease. Oligoprogressive patients were less likely than oligorecurrent patients to achieve local control.

According to National Comprehensive Cancer Network criteria, 3.1%, 54.7%, and 42.2% had low-, intermediate-, and high-risk disease, respectively.

The study population, which had a median age of 71.8 years, included patients treated initially with radical surgery (20.3%), radical surgery plus adjuvant or salvage radiotherapy (54.7%), radical radiotherapy alone (7.8%), ADT (7.8%), and high intensity focused ultrasound (9.4%). The median time to biochemical relapse was 32.8 months.

Radiotherapy was delivered with a median dose of 42 Gy (range 18–60) in 2–8 fractions. The median dose per fraction was 7.5 Gy. Of the 64 patients, 19 (29.7%) had castration-resistant disease when undergoing SBRT.